Node.js Experimental Permission Model Vulnerabilities Identified

CVE-2024-21896 The permission model protects itself against path traversal attacks by calling path.resolve() on any paths given by the user. If the path is to be treated as a Buffer the implementation uses Buffer.from() to obtain a Buffer from the result of path.resolve(). By monkey-patching Buffer internals namely Buffer.prototype.utf8Write the application can modify the result of path.resolve() which leads to a path traversal vulnerability. This vulnerability affects all users using the experimental permission model in Node.js 20 and Node.js 21. Please note that at the time this CVE was issued the permission model is an experimental feature of Node.js.

CVE-2024-21890 The Node.js Permission Model does not clarify in the documentation that wildcards should be only used as the last character of a file path. For example: ``` --allow-fs-read=/home/node/.ssh/*.pub ``` will ignore `pub` and give access to everything after `.ssh/`. This misleading documentation affects all users using the experimental permission model in Node.js 20 and Node.js 21. Please note that at the time this CVE was issued the permission model is an experimental feature of Node.js.